package com.utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 登陆注册图片验证码生成工具类
 *
 * @author 闫超
 */
public class CodeUtil extends HttpServlet {
    private static final long serialVersionUID = 3110081721876882107L;

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doPost(request, response);
    }

    // 生成数字和字母的验证码  
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        BufferedImage img = new BufferedImage(68, 22,
                BufferedImage.TYPE_3BYTE_BGR);// TYPE_INT_RGB  
        // 得到该图片的绘图对象  
        Graphics g = img.getGraphics();
        Random r = new Random();
        Color c = new Color(255, 255, 255);
        g.setColor(c);
        // 填充整个图片的颜色  
        g.fillRect(0, 0, 68, 22);
        // 向图片中输出数字和字母  
        StringBuffer sb = new StringBuffer();
        char[] ch = "abcdefghijklmnopqrstuvwxyz0123456789".toCharArray();
        int index, len = ch.length;
        for (int i = 0; i < 4; i++) {
            index = r.nextInt(len);
            g
                    .setColor(new Color(r.nextInt(88), r.nextInt(188), r
                            .nextInt(255)));
            g.setFont(new Font("Arial", Font.BOLD | Font.ITALIC, 22));// 输出的字体和大小  
            g.drawString("" + ch[index], (i * 15) + 3, 18);// 写什么数字，在图片的什么位置画  
            sb.append(ch[index]);
        }
        request.getSession().setAttribute("code", sb.toString());
        ImageIO.write(img, "JPG", response.getOutputStream());
    }
}  
